AESSHNA. 181 
very slender, linear, connected or not connected with the stem, 
whose basal (posterior) part forms a suborbicular black spot; male 
with a median dorsal tooth on the base of abd. seg. 10; superior 
appendages subequal to abd. segs. 8+9, having a slight inferior 
swelling at one-fourth their length, superior carina very feeble, no 
Spines, apex acute; inferior appendage very little more than half as 
long as the superiors, about one-fifth as wide at apex as at base. 
Abdomen (excl. apps.), ¢ 43-465, 9 43; apps., d 4-5, 9 2; hind 
wing, ¢ 44-45, 2 45; costal edge of pterostigma, front wing, 
5-275 mm... we ee we ee ee ww ew we Be brevifrons *. 
§ II. Subnodal sector forking under the pterostigma or at the level of its 
proximal end, with two rows of cells between the fork at the level of the 
distal end of the pterostigma ; proximal side of the discoidal triangle of 
the hind wings usually, but not always, less than half as long as the 
posterior side; no ventral tubercle on abdominal segment 1; males with 
no dorsal teeth or carinze on segment 10, anal triangle 2-celled. (Coryph- 
eschna, Wllmsn.) 
-F. Thorax with well-marked brown bands at the mid-dorsal carina, the 
humeral and second lateral sutures; abdomen chiefly dark brown or 
black; face bright green, the superior transverse curved groove on 
the anterior surface usually not black; inferior appendage of males 
reaching to mid-length of the superiors. 
G. Size smaller; frons with (g ?) or without (some 2 ) a black T-spot 
superiorly ; superior appendages of the male with a deep sub- 
quadrangular incision on the inner margin at three-fourths their 
length; those of the female very short. Abdomen (excl. apps.), 
3 50-58, 9 57-64; apps., J 5-6, 9 15; hind wing, $ 46-49, 
@ 48-50; costal edge of pterostigma, front wing,4.mm.. . . . 6. luteipennis. 
GG. Size larger; frons with a black T-spot superiorly ; superior 
appendages of the male with entire margins, those of the female 
very long. Abdomen (excl. apps.), ¢ 58-61, 2 65; apps., ¢ 7-7°75, 
? 1:4; hind wing, § 55-59, 2 58-60; costal edge of pterostigma, 
front wings,6mm. . . 2. 1 ee we we ee ww ingens. 
FF, Thorax with no brown markings or with these reduced to lines; 
. superior appendages of the males with entire margins. __ 
H. Frons with a black T-spot superiorly, abdomen chiefly dark brown 
or black. 
J. Size larger; face bright green, the superior transverse curved groove 
on the anterior surface of the frons usually not black or dark 
brown; inferior appendage of the male reaching to about three- 
fifths of the length of the superior appendages. Abdomen (excl. 
* Tt is possible that some venational characters could be employed to distinguish Z, brevifrons, but having 
studied only three individuals I cannot estimate the probable variability of these features. 
